/*
 Copyright  2002-2004 MySQL AB, 2008 Sun Microsystems
 All rights reserved. Use is subject to license terms.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.com.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; version 2 of the
  License.

  This program is distributed in the hope that it will be useful,  
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA



 */
package com.mysql.jdbc;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.sql.SQLException;

/**
 * Simplistic implementation of java.sql.Clob for MySQL Connector/J
 * 
 * @author Mark Matthews
 * @version $Id$
 */
public class Clob implements java.sql.Clob, OutputStreamWatcher, WriterWatcher {
	private String charData;
	private ExceptionInterceptor exceptionInterceptor;
	
    Clob(ExceptionInterceptor exceptionInterceptor) {
        this.charData = "";
        this.exceptionInterceptor = exceptionInterceptor;
    }
    
	Clob(String charDataInit, ExceptionInterceptor exceptionInterceptor) {
		this.charData = charDataInit;
		this.exceptionInterceptor = exceptionInterceptor;
	}

	/**
	 * @see java.sql.Clob#getAsciiStream()
	 */
	public InputStream getAsciiStream() throws SQLException {
		if (this.charData != null) {
			return new ByteArrayInputStream(this.charData.getBytes());
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#getCharacterStream()
	 */
	public Reader getCharacterStream() throws SQLException {
		if (this.charData != null) {
			return new StringReader(this.charData);
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#getSubString(long, int)
	 */
	public String getSubString(long startPos, int length) throws SQLException {
		if (startPos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.6"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		int adjustedStartPos = (int)startPos - 1;
		int adjustedEndIndex = adjustedStartPos + length;
		
		if (this.charData != null) {
			if (adjustedEndIndex > this.charData.length()) {
				throw SQLError.createSQLException(Messages.getString("Clob.7"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
			}

			return this.charData.substring(adjustedStartPos, 
					adjustedEndIndex);
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#length()
	 */
	public long length() throws SQLException {
		if (this.charData != null) {
			return this.charData.length();
		}

		return 0;
	}

	/**
	 * @see java.sql.Clob#position(Clob, long)
	 */
	public long position(java.sql.Clob arg0, long arg1) throws SQLException {
		return position(arg0.getSubString(0L, (int) arg0.length()), arg1);
	}

	/**
	 * @see java.sql.Clob#position(String, long)
	 */
	public long position(String stringToFind, long startPos)
			throws SQLException {
		if (startPos < 1) {
			throw SQLError.createSQLException(
					Messages.getString("Clob.8") //$NON-NLS-1$
							+ startPos + Messages.getString("Clob.9"), SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor); //$NON-NLS-1$
		}

		if (this.charData != null) {
			if ((startPos - 1) > this.charData.length()) {
				throw SQLError.createSQLException(Messages.getString("Clob.10"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
			}

			int pos = this.charData.indexOf(stringToFind, (int) (startPos - 1));

			return (pos == -1) ? (-1) : (pos + 1);
		}

		return -1;
	}

	/**
	 * @see java.sql.Clob#setAsciiStream(long)
	 */
	public OutputStream setAsciiStream(long indexToWriteAt) throws SQLException {
		if (indexToWriteAt < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.0"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		WatchableOutputStream bytesOut = new WatchableOutputStream();
		bytesOut.setWatcher(this);

		if (indexToWriteAt > 0) {
			bytesOut.write(this.charData.getBytes(), 0,
					(int) (indexToWriteAt - 1));
		}

		return bytesOut;
	}

	/**
	 * @see java.sql.Clob#setCharacterStream(long)
	 */
	public Writer setCharacterStream(long indexToWriteAt) throws SQLException {
		if (indexToWriteAt < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.1"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		WatchableWriter writer = new WatchableWriter();
		writer.setWatcher(this);

		//
		// Don't call write() if nothing to write...
		//
		if (indexToWriteAt > 1) {
			writer.write(this.charData, 0, (int) (indexToWriteAt - 1));
		}

		return writer;
	}

	/**
	 * @see java.sql.Clob#setString(long, String)
	 */
	public int setString(long pos, String str) throws SQLException {
		if (pos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.2"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		if (str == null) {
			throw SQLError.createSQLException(Messages.getString("Clob.3"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		StringBuffer charBuf = new StringBuffer(this.charData);

		pos--;

		int strLength = str.length();

		charBuf.replace((int) pos, (int) (pos + strLength), str);

		this.charData = charBuf.toString();

		return strLength;
	}

	/**
	 * @see java.sql.Clob#setString(long, String, int, int)
	 */
	public int setString(long pos, String str, int offset, int len)
			throws SQLException {
		if (pos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.4"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		if (str == null) {
			throw SQLError.createSQLException(Messages.getString("Clob.5"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		StringBuffer charBuf = new StringBuffer(this.charData);

		pos--;

		String replaceString = str.substring(offset, len);

		charBuf.replace((int) pos, (int) (pos + replaceString.length()),
				replaceString);

		this.charData = charBuf.toString();

		return len;
	}

	/**
	 * @see com.mysql.jdbc.OutputStreamWatcher#streamClosed(byte[])
	 */
	public void streamClosed(WatchableOutputStream out) {
		int streamSize = out.size();

		if (streamSize < this.charData.length()) {
			try {
				out.write(StringUtils
						.getBytes(this.charData, null, null, false, null, this.exceptionInterceptor),
						streamSize, this.charData.length() - streamSize);
			} catch (SQLException ex) {
				//
			}
		}

		this.charData = StringUtils.toAsciiString(out.toByteArray());
	}

	/**
	 * @see java.sql.Clob#truncate(long)
	 */
	public void truncate(long length) throws SQLException {
		if (length > this.charData.length()) {
			throw SQLError.createSQLException(
					Messages.getString("Clob.11") //$NON-NLS-1$
							+ this.charData.length()
							+ Messages.getString("Clob.12") + length + Messages.getString("Clob.13"), this.exceptionInterceptor); //$NON-NLS-1$ //$NON-NLS-2$
		}

		this.charData = this.charData.substring(0, (int) length);
	}

	/**
	 * @see com.mysql.jdbc.WriterWatcher#writerClosed(char[])
	 */
	public void writerClosed(char[] charDataBeingWritten) {
		this.charData = new String(charDataBeingWritten);
	}

	/**
	 * @see com.mysql.jdbc.WriterWatcher#writerClosed(char[])
	 */
	public void writerClosed(WatchableWriter out) {
		int dataLength = out.size();

		if (dataLength < this.charData.length()) {
			out.write(this.charData, dataLength, this.charData.length()
					- dataLength);
		}

		this.charData = out.toString();
	}

	public void free() throws SQLException {
		this.charData = null;
	}

	public Reader getCharacterStream(long pos, long length) throws SQLException {
		return new StringReader(getSubString(pos, (int)length));
	}
}
